The Kali Linux operating system allows the ROOT user to send a command which will crash the entire Kali Linux environment.
The command has only been tested on the Kali Linux operating system but the chance is very high that it will also run on other Linux operating systems.
The code will crash the Kali Linux environment and it will disallow it to recover from the crash. The only way to get the Kali Linux running is to restart the operating system.
What basically happened is that the one line command asked the operating system to keep opening process very fast for an infinite period of time.